The invention relates to apparatus for burning wood and the like and particularly to apparatus for controlling the flow of combustion products. While the invention has particular application to controlling the flow of combustion products from stoves which burn wood it will be understood that it also has application to other apparatus which burns other fuels.
The prior art application for controlling the flow of combustion products from a combustion chamber has not resulted in optimum safety and efficiency of operation. The prior art apparatus includes the well known damper which is, of course, merely a disc shaped member which is mounted for rotation on an elongated member which extends through the sides of the flue. The damper has the function of varying the rate at which the combustion products are allowed to escape from a combustion chamber and hence also as to control the amount of air which can be drawn into a combustion chamber. Such prior art apparatus has not been wholly satisfactory because the apparatus has been particulary vulnerable to the accumulation of flamable matter such as creosote on the interior surface of the flue. It is known that the accumulation of combustible matter on the interior of the flue is considerably reduced if the temperature of the flue is maintained at an elevated temperature. At least some people believe that a temperature of 400 degrees F. is necessary to avoid the accumulation of undesirable combustible products such as creosote and the like. The applicant has found that a primary reason that flue ducts are not raised to a sufficiently high temperature (to avoid the accumulation of creosote and other combustible materials in the flue) is that the velocity of the gases is not sufficient.
It is a primary object of the invention to provide combustion gas control apparatus which will have flow characteristics which will tend to avoid the accumulation of combustible combustion products in the flue.
It is another object of the invention to provide apparatus which will maintain a relatively high temperature in the exhaust gas duct work, even during periods of low flow of combustion gases from a fire disposed in a combustion chamber.
It is another object of the invention to provide apparatus which will be simple to install in existing flue structures.
It is yet another object of the invention to provide apparatus which will be inexpensive to manufacture.